﻿CANYON 
  FERRY 
  FOSSIL 
  VERTEBRATES 
  — 
  ^WHITE 
  

  

  433 
  

  

  made. 
  Hypertragulus 
  and 
  Hypisodus 
  appear 
  to 
  be 
  restricted 
  to 
  the 
  

   plains 
  and, 
  like 
  the 
  felids, 
  may 
  have 
  found 
  the 
  mountains 
  climatically 
  

   unsuitable. 
  Heteromeryx 
  is 
  known 
  from 
  a 
  single 
  specimen 
  and 
  there- 
  

   fore 
  unsuited 
  for 
  this 
  study. 
  The 
  same 
  is 
  true 
  for 
  Pseudoprotoceras. 
  

   Of 
  the 
  Camelidae, 
  Eotylopus 
  is 
  known 
  from 
  only 
  three 
  or 
  four 
  specimens 
  

   and 
  consequently 
  is 
  unsuitable 
  for 
  this 
  study. 
  Poebrotherium 
  appears 
  

   to 
  be 
  common 
  to 
  both 
  Provinces 
  but 
  the 
  remains 
  in 
  the 
  mountain 
  

   area 
  are 
  very 
  fragmentary 
  and 
  consequently 
  the 
  genus 
  is 
  unsuitable 
  

   for 
  this 
  study. 
  

  

  Table 
  4. 
  — 
  Distribution 
  of 
  genera 
  in 
  the 
  Lower 
  and 
  Middle 
  Oligocene 
  

  

  •Subfamilies 
  to 
  which 
  these 
  genera 
  belong 
  are 
  believed 
  to 
  be 
  immigrants 
  to 
  North 
  America 
  from 
  Eurasia 
  

   in 
  Early 
  Oligocene 
  times 
  (Simpson. 
  1947). 
  

  

  Table 
  4 
  reveals 
  some 
  very 
  striking 
  contrasts 
  between 
  the 
  faunas 
  of 
  

   the 
  two 
  Provinces, 
  particularly 
  in 
  the 
  number 
  of 
  genera 
  in 
  the 
  Plains 
  

   Province 
  which 
  are 
  not 
  yet 
  known 
  from 
  the 
  intermountain 
  basins. 
  

   Most 
  of 
  these 
  forms 
  are 
  medium 
  to 
  large 
  in 
  size 
  and 
  the 
  subfamily, 
  

   at 
  least, 
  would 
  be 
  recognizable 
  on 
  very 
  fragmentary 
  evidence. 
  Con- 
  

   sequently 
  their 
  nondiscovery 
  at 
  Pipestone 
  Springs 
  indicates, 
  if 
  not 
  

   complete 
  absence, 
  that 
  only 
  occasional 
  stragglers 
  entered 
  the 
  area 
  

   during 
  cycles 
  of 
  maximum 
  abundance. 
  Four 
  of 
  these 
  genera, 
  embrac- 
  

   ing 
  three 
  subfamilies, 
  are 
  believed 
  to 
  be 
  immigrants 
  from 
  Eurasia. 
  

   One 
  of 
  the 
  subfamilies, 
  the 
  Anthracotherinae, 
  with 
  its 
  hippopotamus- 
  

   like 
  habits, 
  quite 
  obviously 
  would 
  have 
  found 
  the 
  smaller, 
  swifter 
  moun- 
  

   tain 
  streams 
  entirely 
  unsuited 
  to 
  its 
  way 
  of 
  life. 
  In 
  the 
  case 
  of 
  Plesictis 
  

   and 
  Deinictis 
  (if 
  this 
  is 
  the 
  true 
  situation), 
  it 
  would 
  appear 
  that 
  a 
  

   temperature 
  factor 
  was 
  involved. 
  Of 
  the 
  nonmigrant 
  genera, 
  one 
  

   family, 
  the 
  Hypertragulidae, 
  is 
  of 
  special 
  interest 
  as 
  only 
  one 
  genus, 
  

   Leptomeryx, 
  appears 
  to 
  have 
  been 
  able 
  to 
  invade 
  the 
  mountains 
  and 
  

  

  